What is wrong with you guys? What is the difference? My 924 was a Martini special edition and it handled VERY WELL. The weakness was the engine block, to be sure, and I did everything in my power to improve performance, by advancing the ignition, improving the ignition, exhaust, air filter, and several other things. Still, the motor had 135,000 miles on it, when I got it, so improved sparkplugs seemed to help.
How many here can work and tune your own auto engine?

I know have known Jack Bybee well, for more than 15 years. I was skeptical at first, but then, I trust my ears in the privacy of my own home.
The quantum 'purifiers' work with an exotic rare earth oxide. There were two reasons why it was classified for about 40 years: One, the fact that they work at all, to reduce a certain kind of noise, and two, that the primary ingredient that made them work, came from the Soviet Union, during 'the cold war'. The Soviets would have stopped shipments of the stuff, if they knew what was being done with it.
I can state this now, because a year or so ago, Jack Bybee told Dimitri this, over lunch. Dimitri can verify this for you, if you insist.
Today's Bybee devices are smaller and apparently better than the original devices. If you could ever see one, up close, you would come to realize that it is not something that you initially make in a garage. I showed SY some exposed units, but then he doesn't believe in virtually anything of this kind.